Technical Information

ATEX Directive

What Is ATEX Directive 94/9/EC?

The ATEX Directive (‘ATmospheres EXplosibles’) 94/9/EC is a directive adopted by the European Union (EU) to facilitate free trade in the EU by aligning the technical and legal requirements in the member states for products intended for use in potentially explosive atmospheres. It is important to note that ATEX has not replaced CENELEC. CENELEC design standards are still used.

Who Needs to Comply with the ATEX Directive?

Manufacturers of mechanical and electrical equipment, as well as protective systems, intended for safe operation in and around potentially explosive atmospheres and who wish to place their products on the market within the European Union need to comply with the ATEX Directive.

ATEX Groups and Categories

Equipment and Products that fall within the scope of the Directive are divided into two Groups:

Group I comprises of equipment intended for use in mines, above and below ground.

Group II comprises of equipment intended for use in other locations endangered by explosive atmospheres.

Equipment and Products in each Group are divided into Categories based on the level of protection required. The categories are as follows:

Group 1

Category M1 – Equipment in this category is required to remain functional with an explosive atmosphere present.

Category M2 – This equipment is intended to be de-energized in the event of an explosive atmosphere forming.

Group II

Category 1 – Equipment in this category is intended for use in areas in which explosive atmospheres caused by mixtures of air and gases, vapors or mists or by air/dust mixtures are present continuously, for long periods or frequently.

Category 2 – Equipment in this category is intended for use in areas in which explosive atmospheres caused by gases, vapors, mists or air/dust mixtures are likely to occur.

Category 3 – Equipment in this category is intended for use in areas in which explosive atmospheres caused by gases, vapors, mists or air/dust mixtures are unlikely to occur or, if they do occur, are likely to do so only infrequently and for a short period only.

ATEX Zones

In addition to the ATEX Directive 94/9/EC, which covers the safety requirements for equipment to be used in potentially explosive atmospheres, there is an additional European ATEX Directive, 99/92/EC. This is also known as the ‘ATEX Workplace Directive’ or ‘ATEX 137′ and highlights what employers must do to minimize the risk to workers from explosive atmospheres.

ATEX 137 also classifies hazardous areas where an explosive atmosphere could form, by type of hazard, into the following ‘Zones’.

Hazard – Gas, Mists or Vapors

Zone 0 – A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapor or mist is present continuously or for long periods or frequently

Zone 1 – A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapor or mist is likely to occur in normal operation occasionally.

Zone 2 – A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapor or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only.

Zone 20 – A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently.

Zone 21 – A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally.

Zone 22 – A place in which an explosive atmosphere in the form or a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only.